Osmotic Pressure of Aqueous Chondroitin Sulfate Solution: A Molecular Modeling Investigation
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Bathe_Osmotic pressure.pdf
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Author(s)
Bathe, Mark
Rutledge, Gregory C.
Grodzinsky, Alan J.
Tidor, Bruce
Date Issued
October 2005
Journal
Biophysical Journal
Publisher
Elsevier
Citation
Bathe, Mark, Gregory C. Rutledge, Alan J. Grodzinsky, and Bruce Tidor. "Osmotic Pressure of Aqueous Chondroitin Sulfate Solution: A Molecular Modeling Investigation." Biophysical Journal Volume 89, Issue 4, October 2005: 2357–2371. © 2005 The Biophysical Society
Version
Final published version
Abstract
The osmotic pressure of chondroitin sulfate (CS) solution in contact with an aqueous 1:1 salt reservoir of fixed ionic strength is studied using a recently developed coarse-grained molecular model. The effects of sulfation type (4- vs. 6-sulfation), sulfation pattern (statistical distribution of sulfate groups along a chain), ionic strength, CS intrinsic stiffness, and steric interactions on CS osmotic pressure are investigated. At physiological ionic strength (0.15 M NaCl), the sulfation type and pattern, as measured by a standard statistical description of copolymerization, are found to have a negligible influence on CS osmotic pressure, which depends principally on the mean volumetric fixed charge density. The intrinsic backbone stiffness characteristic of polysaccharides such as CS, however, is demonstrated to contribute significantly to its osmotic pressure behavior, which is similar to that of a solution of charged rods for the 20-disaccharide chains considered. Steric excluded volume is found to play a negligible role in determining CS osmotic pressure at physiological ionic strength due to the dominance of repulsive intermolecular electrostatic interactions that maintain chains maximally spaced in that regime, whereas at high ionic-strength steric interactions become dominant due to electrostatic screening. Osmotic pressure predictions are compared to experimental data and to well-established theoretical models including the Donnan theory and the Poisson-Boltzmann cylindrical cell model.
MIT Department
Massachusetts Institute of Technology. Department of Biological Engineering
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1529/biophysj.105.067918
